1/* 2 * locks.S: SMP low-level lock primitives on Sparc. 3 * 4 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu) 5 * Copyright (C) 1998 Anton Blanchard (anton@progsoc.uts.edu.au) 6 * Copyright (C) 1998 Jakub Jelinek (jj@ultra.linux.cz) 7 */ 8 9#include <asm/ptrace.h> 10#include <asm/psr.h> 11#include <asm/smp.h> 12#include <asm/spinlock.h> 13 14 .text 15 .align 4 16 17 /* Read/writer locks, as usual this is overly clever to make it 18 * as fast as possible. 19 */ 20 21 /* caches... */ 22___rw_read_enter_spin_on_wlock: 23 orcc %g2, 0x0, %g0 24 be,a ___rw_read_enter 25 ldstub [%g1 + 3], %g2 26 b ___rw_read_enter_spin_on_wlock 27 ldub [%g1 + 3], %g2 28___rw_read_try_spin_on_wlock: 29 andcc %g2, 0xff, %g0 30 be,a ___rw_read_try 31 ldstub [%g1 + 3], %g2 32 xnorcc %g2, 0x0, %o0 /* if g2 is ~0, set o0 to 0 and bugger off */ 33 bne,a ___rw_read_enter_spin_on_wlock 34 ld [%g1], %g2 35 retl 36 mov %g4, %o7 37___rw_read_exit_spin_on_wlock: 38 orcc %g2, 0x0, %g0 39 be,a ___rw_read_exit 40 ldstub [%g1 + 3], %g2 41 b ___rw_read_exit_spin_on_wlock 42 ldub [%g1 + 3], %g2 43___rw_write_enter_spin_on_wlock: 44 orcc %g2, 0x0, %g0 45 be,a ___rw_write_enter 46 ldstub [%g1 + 3], %g2 47 b ___rw_write_enter_spin_on_wlock 48 ld [%g1], %g2 49 50 .globl ___rw_read_enter 51___rw_read_enter: 52 orcc %g2, 0x0, %g0 53 bne,a ___rw_read_enter_spin_on_wlock 54 ldub [%g1 + 3], %g2 55 ld [%g1], %g2 56 add %g2, 1, %g2 57 st %g2, [%g1] 58 retl 59 mov %g4, %o7 60 61 .globl ___rw_read_exit 62___rw_read_exit: 63 orcc %g2, 0x0, %g0 64 bne,a ___rw_read_exit_spin_on_wlock 65 ldub [%g1 + 3], %g2 66 ld [%g1], %g2 67 sub %g2, 0x1ff, %g2 68 st %g2, [%g1] 69 retl 70 mov %g4, %o7 71 72 .globl ___rw_read_try 73___rw_read_try: 74 orcc %g2, 0x0, %g0 75 bne ___rw_read_try_spin_on_wlock 76 ld [%g1], %g2 77 add %g2, 1, %g2 78 st %g2, [%g1] 79 set 1, %o1 80 retl 81 mov %g4, %o7 82 83 .globl ___rw_write_enter 84___rw_write_enter: 85 orcc %g2, 0x0, %g0 86 bne ___rw_write_enter_spin_on_wlock 87 ld [%g1], %g2 88 andncc %g2, 0xff, %g0 89 bne,a ___rw_write_enter_spin_on_wlock 90 stb %g0, [%g1 + 3] 91 retl 92 mov %g4, %o7 93